Instruction file imported from fkucukkara/authn-authz-playground (.github/instructions/csharp-testing.instructions.md). Copyright stays with the author.

C# Testing Best Practices

Testing Framework Guidelines

Test Structure

• Follow the Arrange-Act-Assert (AAA) pattern
• One assertion per test method when possible
• Use descriptive test method names that explain the scenario

Naming Conventions

// ✅ Good - Descriptive test names
[Test]
public void CalculateTotal_WithValidItems_ReturnsCorrectSum()
{
    // Arrange
    var calculator = new Calculator();
    var items = new[] { 1.5m, 2.3m, 4.2m };
    
    // Act
    var result = calculator.CalculateTotal(items);
    
    // Assert
    result.Should().Be(8.0m);
}

Test Data Management

• Use test builders or factory methods for complex object creation
• Leverage data-driven tests for multiple scenarios
• Keep test data focused and minimal

Mocking Guidelines

• Mock external dependencies and infrastructure concerns
• Don't mock value objects or simple data containers
• Use meaningful mock setups that reflect real behavior

Integration Tests

• Test against real databases using test containers when possible
• Use separate test configuration and connection strings
• Clean up test data after each test run

Performance Testing

• Include performance tests for critical paths
• Set realistic performance thresholds
• Use BenchmarkDotNet for micro-benchmarks

Test Categories

• Unit Tests: Fast, isolated, test single components
• Integration Tests: Test component interactions
• End-to-End Tests: Test complete user scenarios
• Contract Tests: Verify API contracts and behavior